While me personally being busy til and broke ingame have not been able to fish yet a fish bowl item you could place fish in would be cool
Also will add fish tanks for maps
Idea 1 the fish bowl has a creative and cotton version that will be able to be placed and see fish swim around also will have bigger sizes to store more fish
Idea 2 the fishbowl will follow you around like a pet so you can have your favorite fish follow you (maybe the fish will be saved in you inventory in the fishbowl to ease of use)